Chappy,
The AI does pretty good in OFF (no lawn darts as far as I've seen). Actually the flight modeling reminds me of what FS-WWI presented, which means critical angle of attack stalls aren't emphasized, and instead departures seem to occur mostly as a result of airspeed/energy loss.
I think much of this has to do with CFS3's WW2-type coding and the ability of the AI to (mis)handle pitching changes, which was exactly the problem we encountered when trying to get (more)real with the FS-WWI FMs.
OFF is very immersive in sight, sound, and feel, with the flight modeling varied enough to be rewarding to fly and fight, while dealing well with the basic limitations of grafting a WWI sim over a base-WW2 platform.
Actually, OFF is pretty impressive in this it's first "release", and to me the mod has a quality approaching an "out of the box" build.
What really excites me, is that OFF shows what a state of the art WWI sim could be like, and portends well for what is possible in this genre if the effort is really put into it!
In the meantime, all WWI flight sim fans should try OFF if their computer can handle running CFS3, because it is a good experience, especially since it's free!
(not a review here, as I've not put nearly enough time into flying OFF, but I'm convinced WWI fans will find it worthy of their time)